Field of the Disclosure
The invention generally relates to control valves including a trim assembly having a plurality of pressure reducing openings and more specifically to a control valve trim having a first plurality of pressure reducing openings and a second plurality of noise reducing vents.
Related Technology
Fluid valves control the flow of fluid from one location to another. When the fluid valve is in a closed position, high pressure fluid on one side is prevented from flowing to a lower pressure location on the other side of the valve. Often fluid valves contain a movable fluid control member and a seat of some sort that cooperates with the fluid control member to control fluid flow through the valve. In some cases it may be desirable to characterize fluid as it flows through the valve, for example, to reduce pressure. In these cases, a trim assembly may be used that includes a cage with a plurality of pressure reducing openings. The openings may be sized and shaped to characterize fluid flow through the trim assembly, for example by reducing fluid pressure. However, the pressure reducing openings create turbulent flow downstream of the valve trim, which results in unwanted noise.
Turning now to FIG. 1, a known control valve 10 is illustrated. The control valve 10 includes a valve body 12 having a fluid inlet 14 and a fluid outlet 16 connected by a fluid passageway 18. A trim assembly 20 is disposed within the valve body 12 between the fluid inlet 14 and the fluid outlet 16. The trim assembly 20 includes a cage 22 and a seat 24. A fluid control member, such as a plug 26 is disposed within the cage 22 and the plug 26 interacts with the seat 24 to control fluid flow through the valve body 12. A stem 28 is connected to the plug 26 at one end and an actuator 30 at another end. The actuator 30 controls movement of the plug 26 within the cage 22.
As illustrated in FIG. 2, the cage 22 includes a first end 32 and a second end 36. A cage wall 38 extends between the first end 32 and the second end 36, the cage wall 38 forming a hollow central bore within which the valve plug 26 slides to control fluid flow through the cage 22. A plurality of cage openings 40 is formed in the cage wall 38. The plurality of cage openings 40 characterize fluid flowing through the cage 22, by for example, reducing the pressure of the fluid as it flows through the openings 40. The openings may be generally circular in shape with a central axis A that is perpendicular to a longitudinal axis B of the cage 22.